With reference to your original query on setting up the brakes, you may wish to go to the source and view the Austin Service Journal article reproduced on the Cornwall Austin Seven Club website. Look in their Technical articles section, press the blue button on the left labelled Austin Seven Journal and scroll down the page to see the list of sections reproduced. This is the most comprehensive description that I have found.
Regards,
Stuart
01-07-2024, 02:23 PM (This post was last modified: 01-07-2024, 02:24 PM by Reckless Rat.)
There seems to be two major things not right with your set-up. Firstly, it shouldn't be necessary to have the Girling adjusters turned fully back in order to stop the brakes binding. Can you show us a photo of the brake shoes & linings you're using - that might help.
The levers should not be pointing forward 45° when at rest, and cotter pin orientation may not be helping. Ideally they should be vertical when fully applied, relative to the King Pin.
Some more photos will certainly assist, but failing that I would suggest you make contact with a fellow A7 enthusiast in NZ and get them to have a look. The fact that you say you've had to lengthen the front brake cable rings alarm bells.
The brake cable was custom made anyway. The car is a Special. There is probably 2 inches difference per side, with the levers now at different positions.
The brake linings are bonded on, with only minimal clearance as per modern brakes, I guess. The brake company dressed them to the drums. I would guess that all is well there.
I'd say that the biggest problem here are the brake cams. They and the levers are new from the Seven Workshop. The cams had the cotter rebates at a markedly different angle to the originals (which probably aren't the actual "originals" for the axle). I bought new cams because the old ones had the levers pulled back towards the rear of the car with the brakes off. I don't know what to do, unless I grind the shoes so that they are half worn, and place the cams at an almost full-on position with the brakes in the off position.
I haven't been able to drive it with the new brakes because the battery is almost dead, especially because it is winter here. Time for a new battery.
You are correct compensator should have equal spacing front and rear., if yours is not it is because of cable length/tension. You should set up the back plate adjusters as suggested and then adjust the respective cable tensions to get the compensator disposition equalised.
04-07-2024, 03:34 AM (This post was last modified: 04-07-2024, 03:35 AM by falcott.)
Hi Ruairidh, the linings are approximately 4.2 - 4.4 mm thick. Including the shoe they are approximately 7.0 mm thick.
Here are the photos requested.
You can see that the adjusters are wound right off, so the drums have *just* enough clearance to graze the shoes slightly at one point when spinning the drum (the drums being slightly out of round).
The brake lever is to the front of the car.
The other photo shows the old cam against the new cam, showing the remarkable difference in the cotter position.
When I had shoes re-lined by Saftek they quoted the following sizes for A7 linings.
Cheers
Howard
———————————————
Hi Howard
With reference to your enquiry
Most of the Austin 7 shoes list 3/16"( 4.8mm ) as standard thickness
The exception being shoes produced in the late 30s
These list the thickness as 5/32" ( 4mm )
Cost to reline - £9.60 each + vat & return postage ( based on 20 shoes )
Turnaround 2-3 days
Kind Regards
Paul Riley
Saftek Friction Ltd
Unit 1
Rawfolds Ind Estate
Bradford Road
Cleckheaton
West Yorkshire
BD19 5LT
Tel 01274 862666
04-07-2024, 08:35 AM (This post was last modified: 04-07-2024, 08:38 AM by Stumpi.)
I have just had a set of rear shoes relined by Saftek(posted Monday back Thursday).
I asked for 5mm thick material as the drums are 7.1 internal diameter. Assembly is almost done with new bearings and cams with new springs.
Just need to adjust the cables.
Over many years I have used a variety of lubricants and pastes on the plungers and adjusters with poor results,this time I am using ceramic grease .results to follow,
Looking at the cams looks as though you may have a front and rear,the ones from A7components are clearly marked.
The advantage of semi-girling is that the smaller cams and longer levers give more leverage, so that for a given cable tension more force is applied to the shoes for more braking force. The downside is that lining wear has a more pronounced effect on pedal travel, so there had to be an easy way to re-adjust at each wheel without messing about with cable lengths as used to be the case. Hence the square headed adjusters.
With shoes adjusted for minimal running clearance and brakes off, the flat cams will be at their minimum position and will sit vertically between the steel plungers. The lever should then be more or less vertical, and the machined cotter pin slot more or less horizontal, so the slot will be at right angles to the cam. Presumably one has to factor in the need for the levers to actually be slightly ahead of vertical when off, so that with their (small) travel they are truly vertical when on. Also, one has to allow for the small taper angle of the cotter pin. The cam on the left of your photo is therefore what I would expect to see. The cams are handed left and right, and don't forget that rear cams are also different to fronts. The heads used to be stamped with letters to identify them.
Lining thickness shouldn't upset the above, provided you can still adjust for the correct running clearance ( which you can - just ). Clearly, if you had thinner linings and deliberately mis-adjusted them for a large running clearance you could make the levers travel more between the brakes off and brakes on states, so that they would be vertical with the brakes on. But this isn't how they are supposed to work and would give you a very long pedal travel.
The photo below is of my own setup, the levers are from Seven Workshop but I cannot remember the source of the cams. The handbrake is on (which fully applies the rear brakes and lightly applies the front brakes) but the travel from off to on is pretty small. As you can see, the lever sits more or less vertically and the cotter nut is to the rear.
You have the cotters correctly orientated for a Girling system and although the levers are forward and down, the ends are sitting up higher than I would expect.
This is one of my own cars, with handbrake fully applied (note, I prefer to set up the system up so that front brakes are fully on with the rear just starting to come on).
I have measured several NOS linings that I have here and they all measure exactly 4mm.
The lack of top adjustment on your car can only really be attributed to the linings being too thick, even with new I can normally still get a couple of clicks using second hand drums.
The lever position is down to the cotter slot in the cams and, looking carefully at yours, I do wonder if you have a pair intended for the rear brakes.
I am away from my workshop but I may have some spare cams in the car and if that is the case I will post a photo later for you to use as a comparison.
